1. Field of the Invention
The device of this invention resides in the area of safety guards for circular power saws and more particularly relates to a movable saw guard.
2. Description of the Prior Art
Manually held circular power saws are frequently equipped with a retractable blade guard disposed beneath the saw blade which substantially encloses the teeth of the lower half of the saw blade that would otherwise be exposed below the base of the saw. The purpose of the guard is to prevent contact of the blade's cutting teeth with fingers or other parts of the person operating the saw. Mounted on such saws is usually a fixed upper saw guard which encloses the upper half of the saw blade. Typically, the upper saw guard is adapted to receive the retractable lower guard as the saw blade engages the material to be cut. The lower guard is then forced in a rearward arc, exposing the blade. When the pressure of the material is removed from the lower guard, a spring returns the lower guard to its original position to re-enclose the teeth of the blade.
At times, however, the lower retractable guard interferes with the operation of the saw. The operator of the saw may encounter situations where the lower guard does not easily retract, making it difficult if not impossible to advance the saw through the material to be cut. To resolve this dilemma, the operator of the saw may use one hand to manually rotate the guard out of the way and hold it in a retracted position. This action causes the operator to only use one hand, instead of two hands, to hold and control the saw and increases the risk of physical harm to the operator from the exposed saw blade.
Prior art devices have been developed to solve this problem. U.S. Pat. No. 2,722,246 to Arnoldy utilizes a solenoid which is energized to swing the saw guard to a retracted position. The guard is returned to its original protective position by a conventional guard return spring mounted on the solenoid plunger when the solenoid is de-energized. U.S. Pat. No. 3,063,481 to Sutherland discloses a saw guard retractor which includes a pivoting lever with a drive wheel powered from the saw motor and adapted to engage the retractable guard upon movement of the lever. The engagement of the drive wheel moves the guard to a retracted position. The activation of a thumb button on the saw handle causes the return of the guard to its protective position. U.S. Pat. No. 3,410,325 to Winther uses magnetic induction to move a retractable saw guard.